A ictator is an authoritarian ruler (e.g. absolutist or autocratic) who assumes sole power over his or her state, though the term is normally not applied to those who acquire such position by regular constitutional means, such as a hereditary absolute monarch, except to denote personal abuse of power. A government that calls its head of state a dictator is called a dictatorship. The word originated as the title of a magistrate in ancient Rome appointed by the Senate to rule the republic in times of emergency (see Roman dictator and justitium). Like the term tyrant, originally a respectable Ancient Greek title, and to a lesser degree autocrat, it came to be used almost exclusively as a non-titular term for oppressive, even abusive rule, yet had rare modern titular uses.